Lay ramps of pipeline laying vessels are normally of variable-configuration design. That is, a lay ramp normally comprises a number of segments hinged to one another and to the laying vessel; and a number of pipeline supports. The position of each segment is adjustable with respect to the laying vessel and/or to the other segments, and each support is fitted adjustably to one of the segments to minimize the forces transmitted to the pipeline, and to define a pipeline configuration designed to minimize stress induced in the pipeline. A lay ramp of this type is described in Applicant's PCT Patent Application No. WO 2011/086100 A2. When laying the pipeline, the lay ramp configuration normally varies slightly to adapt to changing external conditions or to operating parameters of the laying vessel. When laying work is stopped by bad weather, the pipeline is abandoned on the bed of the body of water, and the lay ramp is set to a safety configuration above water.
When the topography of the bed along which the pipeline is to be laid varies considerably, the configuration of the lay ramp varies widely between a first and second work configuration. In this connection, it is important to remember that a path along which to lay the pipeline is determined beforehand, and extends inside a laying corridor (i.e., a theoretical strip along the bed of the body of water). To avoid overstressing the pipeline, this is normally abandoned before changing the configuration of the lay ramp.